The laser burns part of a blood vessel stopping the leakage. Your focal point is an imaginary point in space determined by your lens
A close relative has this edema, and the Dr told him that the conventional laser wouldn’t work because the edema was right at the center of the field of vision at the part of the retina where the focus point is located.
My question to the Dr is, what about the laser used in the study, would it take care of the edema and not disturb the focus-ability?
https://medlineplus.gov/ency/imagepages/19511.htm
Top picture is normal vision, and the light hits the retina.
Not too far behind or too far in front as shown in the other pictures.
The spot with the edema is right where the light hits the retina, the focus point, and it causes the center of vision to be blurred out.